arcade-physics/lib/geom/triangle/GetPoints.js

Use Arcade Physics without Phaser.

"use strict";
/**
 * @author       Richard Davey <rich@photonstorm.com>
 * @copyright    2020 Photon Storm Ltd.
 * @license      {@link https://opensource.org/licenses/MIT|MIT License}
 */
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
const Length_1 = __importDefault(require("../line/Length"));
const Point_1 = __importDefault(require("../point/Point"));
/**
 * Returns an array of evenly spaced points on the perimeter of a Triangle.
 *
 * @function Phaser.Geom.Triangle.GetPoints
 * @since 3.0.0
 *
 * @generic {Phaser.Geom.Point} O - [out,$return]
 *
 * @param {Phaser.Geom.Triangle} triangle - The Triangle to get the points from.
 * @param {number} quantity - The number of evenly spaced points to return. Set to 0 to return an arbitrary number of points based on the `stepRate`.
 * @param {number} stepRate - If `quantity` is 0, the distance between each returned point.
 * @param {(array|Phaser.Geom.Point[])} [out] - An array to which the points should be appended.
 *
 * @return {(array|Phaser.Geom.Point[])} The modified `out` array, or a new array if none was provided.
 */
const GetPoints = (triangle, quantity, stepRate, out) => {
    if (out === undefined) {
        out = [];
    }
    const line1 = triangle.getLineA();
    const line2 = triangle.getLineB();
    const line3 = triangle.getLineC();
    const length1 = (0, Length_1.default)(line1);
    const length2 = (0, Length_1.default)(line2);
    const length3 = (0, Length_1.default)(line3);
    const perimeter = length1 + length2 + length3;
    //  If quantity is a falsey value (false, null, 0, undefined, etc) then we calculate it based on the stepRate instead.
    if (!quantity && stepRate > 0) {
        quantity = perimeter / stepRate;
    }
    for (let i = 0; i < quantity; i++) {
        let p = perimeter * (i / quantity);
        let localPosition = 0;
        const point = new Point_1.default();
        //  Which line is it on?
        if (p < length1) {
            //  Line 1
            localPosition = p / length1;
            point.x = line1.x1 + (line1.x2 - line1.x1) * localPosition;
            point.y = line1.y1 + (line1.y2 - line1.y1) * localPosition;
        }
        else if (p > length1 + length2) {
            //  Line 3
            p -= length1 + length2;
            localPosition = p / length3;
            point.x = line3.x1 + (line3.x2 - line3.x1) * localPosition;
            point.y = line3.y1 + (line3.y2 - line3.y1) * localPosition;
        }
        else {
            //  Line 2
            p -= length1;
            localPosition = p / length2;
            point.x = line2.x1 + (line2.x2 - line2.x1) * localPosition;
            point.y = line2.y1 + (line2.y2 - line2.y1) * localPosition;
        }
        out.push(point);
    }
    return out;
};
exports.default = GetPoints;
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